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Author Shirazi, M.; Neyts, E.C.; Bogaerts, A.
Title DFT study of Ni-catalyzed plasma dry reforming of methane Type A1 Journal article
Year 2017 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 205 Issue 205 Pages 605-614
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract tWe investigated the plasma-assisted catalytic reactions for the production of value-added chemicalsfrom Ni-catalyzed plasma dry reforming of methane by means of density functional theory (DFT). Weinspected many activation barriers, from the early stage of adsorption of the major chemical fragmentsderived fromCH4andCO2molecules up to the formation of value-added chemicals at the surface, focusingon the formation of methanol, as well as the hydrogenation of C1and C2hydrocarbon fragments. Theactivation barrier calculations show that the presence of surface-bound H atoms and in some cases alsoremaining chemical fragments at the surface facilitates the formation of products. This implies that thehydrogenation of a chemical fragment on the hydrogenated crystalline surface is energetically favouredcompared to the simple hydrogenation of the chemical fragment at the bare Ni(111) surface. Indeed, thepresence of hydrogen modifies the electronic structure of the surface and the course of the reactions.We therefore conclude that surface-bound H atoms, and to some extent also the remaining chemicalfragments at the crystalline surface, induce the following effects: they facilitate associative desorption ofmethanol and ethane by increasing the rate of H-transfer to the adsorbed fragments while they impedehydrogenation of ethylene to ethane, thus promoting again the desorption of ethylene. Overall, they thusfacilitate the catalytic conversion of the formed fragments from CH4and CO2, into value-added chemicals.Finally, we believe that the retention of methane fragments, especially CH3, in the presence of surface-boundHatoms (as observed here for Ni) can be regarded as an identifier for the proper choice of a catalystfor the production of value-added chemicals.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000393931000063 Publication Date 2017-01-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-3373 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 9.446 Times cited 26 Open Access OpenAccess
Notes Financial support from the Reactive Atmospheric Plasmaprocessing –eDucation network (RAPID), through the EU 7thFramework Programme (grant agreement no. 606889) is grate-fully acknowledged. The calculations were performed using theTuring HPC infrastructure at the CalcUA core facility of the Univer-siteit Antwerpen, a division of the Flemish Supercomputer CenterVSC, funded by the Hercules Foundation, the Flemish Approved Most recent IF: 9.446
Call Number PLASMANT @ plasmant @ c:irua:139514 Serial 4343
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Author Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C.
Title Self-limiting oxidation in small-diameter Si nanowires Type A1 Journal article
Year 2012 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 24 Issue 11 Pages 2141-2147
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Recently, core shell silicon nanowires (Si-NWs) have been envisaged to be used for field-effect transistors and photovoltaic applications. In spite of the constant downsizing of such devices, the formation of ultrasmall diameter core shell Si-NWs currently remains entirely unexplored. We report here on the modeling of the formation of such core shell Si-NWs using a dry thermal oxidation of 2 nm diameter (100) Si nanowires at 300 and 1273 K, by means of reactive molecular dynamics simulations using the ReaxFF potential. Two different oxidation mechanisms are discussed, namely a self-limiting process that occurs at low temperature (300 K), resulting in a Si core I ultrathin SiO2 silica shell nanowire, and a complete oxidation process that takes place at a higher temperature (1273 K), resulting in the formation of an ultrathin SiO2 silica nanowire. The oxidation kinetics of both cases and the resulting structures are analyzed in detail. Our results demonstrate that precise control over the Si-core radius of such NWs and the SiOx (x <= 2.0) oxide shell is possible by controlling the growth temperature used during the oxidation process.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000305092600021 Publication Date 2012-05-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 9.466 Times cited 45 Open Access
Notes Approved Most recent IF: 9.466; 2012 IF: 8.238
Call Number UA @ lucian @ c:irua:99079 Serial 2976
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Author Eckert, M.; Mortet, V.; Zhang, L.; Neyts, E.; Verbeeck, J.; Haenen, ken; Bogaerts, A.
Title Theoretical investigation of grain size tuning during prolonged bias-enhanced nucleation Type A1 Journal article
Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 23 Issue 6 Pages 1414-1423
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper, the effects of prolonged bias-enhanced nucleation (prolonged BEN) on the growth mechanisms of diamond are investigated by molecular dynamics (MD) and combined MD-Metropolis Monte Carlo (MD-MMC) simulations. First, cumulative impacts of CxHy+ and Hx+ on an a-C:H/nanodiamond composite were simulated; second, nonconsecutive impacts of the dominant ions were simulated in order to understand the observed phenomena in more detail. As stated in the existing literature, the growth of diamond structures during prolonged BEN is a process that takes place below the surface of the growing film. The investigation of the penetration behavior of CxHy+ and Hx+ species shows that the carbon-containing ions remain trapped within this amorphous phase where they dominate mechanisms like precipitation of sp3 carbon clusters. The H+ ions, however, penetrate into the crystalline phase at high bias voltages (>100 V), destroying the perfect diamond structure. The experimentally measured reduction of grain sizes at high bias voltage, reported in the literature, might thus be related to penetrating H+ ions. Furthermore, the CxHy+ ions are found to be the most efficient sputtering agents, preventing the build up of defective material.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000288291400011 Publication Date 2011-02-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 9.466 Times cited 9 Open Access
Notes Iwt; Fwo; Esteem 026019; Iap Approved Most recent IF: 9.466; 2011 IF: 7.286
Call Number UA @ lucian @ c:irua:87642 Serial 3605
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Author Gogoi, A.; Neyts, E.C.; Milošević, M.V.; Peeters, F.M.
Title Arresting aqueous swelling of layered graphene-oxide membranes with H3O+ and OH- ions Type A1 Journal article
Year 2022 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 14 Issue 30 Pages 34946-34954
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Over the past decade, graphene oxide (GO) has emerged as a promising membrane material with superior separation performance and intriguing mechanical/chemical stability. However, its practical implementation remains very challenging primarily because of its undesirable swelling in an aqueous environment. Here, we demonstrated that dissociation of water molecules into H3O+ and OH- ions inside the interlayer gallery of a layered GO membrane can strongly affect its stability and performance. We reveal that H3O+ and OH- ions form clusters inside the GO laminates that impede the permeance of water and salt ions through the membrane. Dynamics of those clusters is sensitive to an external ac electric field, which can be used to tailor the membrane performance. The presence of H3O+ and OH- ions also leads to increased stability of the hydrogen bond (H-bond) network among the water molecules and the GO layers, which further reduces water permeance through the membrane, while crucially imparting stability to the layered GO membrane against undesirable swelling. KEYWORDS: layered graphene-oxide membrane, aqueous stability, H3O+ and OH- ions, external electric field, molecular dynamics
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000835946500001 Publication Date 2022-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 9.5 Times cited 9 Open Access OpenAccess
Notes Approved Most recent IF: 9.5
Call Number UA @ admin @ c:irua:189467 Serial 7127
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Author Wang, Z.; Zhang, Y.; Neyts, E.C.; Cao, X.; Zhang, X.; Jang, B.W.-L.; Liu, C.-jun
Title Catalyst preparation with plasmas : how does it work? Type A1 Journal article
Year 2018 Publication ACS catalysis Abbreviated Journal Acs Catal
Volume 8 Issue 3 Pages 2093-2110
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Catalyst preparation with plasmas is increasingly attracting interest. A plasma is a partially ionized gas, consisting of electrons, ions, molecules, radicals, photons, and excited species, which are all active species for catalyst preparation and treatment. Under the influence of plasma, nucleation and crystal growth in catalyst preparation can be very different from those in the conventional thermal approach. Some thermodynamically unfavorable reactions can easily take place with plasmas. Compounds such as sulfides, nitrides, and phosphides that are produced under harsh conditions can be synthesized by plasma under mild conditions. Plasmas can produce catalysts with smaller particle sizes and controllable structure. Plasma is also a facile tool for reduction, oxidation, doping, etching, coating, alloy formation, surface treatment, and surface cleaning in a simple and direct way. A rapid and convenient plasma template removal has thus been established for zeolite synthesis. It can operate at room temperature and allows the catalyst preparation on temperature-sensitive supporting materials. Plasma is typically effective for the production of various catalysts on metallic substrates. In addition, plasma-prepared transition-metal catalysts show enhanced low-temperature activity with improved stability. This provides a useful model catalyst for further improvement of industrial catalysts. In this review, we aim to summarize the recent advances in catalyst preparation with plasmas. The present understanding of plasma-based catalyst preparation is discussed. The challenges and future development are addressed.
Address
Corporate Author Thesis
Publisher Amer chemical soc Place of Publication Washington Editor
Language Wos 000426804100055 Publication Date 2018-01-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 10.614 Times cited 81 Open Access Not_Open_Access
Notes Approved Most recent IF: 10.614
Call Number UA @ lucian @ c:irua:150880 Serial 4963
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Author Yi, Y.; Wang, X.; Jafarzadeh, A.; Wang, L.; Liu, P.; He, B.; Yan, J.; Zhang, R.; Zhang, H.; Liu, X.; Guo, H.; Neyts, E.C.; Bogaerts, A.
Title Plasma-Catalytic Ammonia Reforming of Methane over Cu-Based Catalysts for the Production of HCN and H2at Reduced Temperature Type A1 Journal article
Year 2021 Publication Acs Catalysis Abbreviated Journal Acs Catal
Volume 11 Issue 3 Pages 1765-1773
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Industrial production of HCN from NH3 and CH4 not only uses precious Pt or Pt−Rh catalysts but also requires extremely high temperatures (∼1600 K). From an energetic, operational, and safety perspective, a drastic decrease in temperature is highly desirable. Here, we report ammonia reforming of methane for the production of HCN and H2 at 673 K by the combination of CH4/NH3 plasma and a supported Cu/silicalite-1 catalyst. 30% CH4 conversion has been achieved with 79% HCN selectivity. Catalyst characterization and plasma diagnostics reveal that the excellent reaction performance is attributed to metallic Cu active sites. In addition, we propose a possible reaction pathway, viz. E-R reactions with N, NH, NH2, and CH radicals produced in the plasma, for the production of HCN, based on density functional theory calculations. Importantly, the Cu/silicalite-1 catalyst costs less than 5% of the commercial Pt mesh catalyst.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000618540300057 Publication Date 2021-02-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 10.614 Times cited Open Access OpenAccess
Notes Universiteit Antwerpen, 32249 ; China Postdoctoral Science Foundation, 2015M580220 2016T90217 ; PetroChina Innovation Foundation, 2018D-5007-0501 ; National Natural Science Foundation of China, 21503032 ; We acknowledge financial support from the National Natural Science Foundation of China [21503032], the China Postdoctoral Science Foundation [grant numbers 2015M580220 and 2016T90217, 2016], the PetroChina Innovation Foundation [2018D-5007-0501], and the TOP research project of the Research Fund of the University of Antwerp [grant ID 32249]. Approved Most recent IF: 10.614
Call Number PLASMANT @ plasmant @c:irua:175880 Serial 6675
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Author Faraji, F.; Neyts, E.C.; Milošević, M.V.; Peeters, F.M.
Title Capillary Condensation of Water in Graphene Nanocapillaries Type A1 Journal Article
Year 2024 Publication Nano Letters Abbreviated Journal Nano Lett.
Volume 24 Issue 18 Pages 5625-5630
Keywords A1 Journal Article; CMT
Abstract Recent experiments have revealed that the macroscopic Kelvin equation remains surprisingly accurate even for nanoscale capillaries. This phenomenon was so far explained by the oscillatory behavior of the solid−liquid interfacial free energy. We here demonstrate thermodynamic and capillarity inconsistencies with this explanation. After revising the Kelvin equation, we ascribe its validity at nanoscale confinement to the effect of disjoining pressure.

To substantiate our hypothesis, we employed molecular dynamics simulations to evaluate interfacial heat transfer and wetting properties. Our assessments unveil a breakdown in a previously established proportionality between the work of adhesion and the Kapitza conductance at capillary heights below 1.3 nm, where the dominance of the work of adhesion shifts primarily from energy to entropy. Alternatively, the peak density of the initial water layer can effectively probe the work of adhesion. Unlike under bulk conditions, high confinement renders the work of adhesion entropically unfavorable.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984 ISBN Additional Links
Impact Factor (up) 10.8 Times cited Open Access
Notes This work was supported by Research Foundation-Flanders (FWO, project No. G099219N). The computational resources used in this work were provided by the HPC core facility CalcUA of the University of Antwerp, and the Flemish Supercomputer Center (VSC), funded by FWO and the Flemish Government. Approved Most recent IF: 10.8; 2024 IF: 12.712
Call Number UA @ lucian @ Serial 9123
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors Type A1 Journal article
Year 2015 Publication Nature communications Abbreviated Journal Nat Commun
Volume 6 Issue 6 Pages 10306
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level.
Address PLASMANT research group, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000367584500001 Publication Date 2015-12-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 12.124 Times cited 37 Open Access
Notes The authors gratefully acknowledge financial support from the Fund of Scientific Research Flanders (FWO), Belgium, grant number 12M1315N. The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. We thank Professor Adri C. T. van Duin for sharing the ReaxFF code. Approved Most recent IF: 12.124; 2015 IF: 11.470
Call Number c:irua:129975 Serial 3990
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Author Chernozem, R., V; Romanyuk, K.N.; Grubova, I.; Chernozem, P., V.; Surmeneva, M.A.; Mukhortova, Y.R.; Wilhelm, M.; Ludwig, T.; Mathur, S.; Kholkin, A.L.; Neyts, E.; Parakhonskiy, B.; Skirtach, A.G.; Surmenev, R.A.
Title Enhanced piezoresponse and surface electric potential of hybrid biodegradable polyhydroxybutyrate scaffolds functionalized with reduced graphene oxide for tissue engineering Type A1 Journal article
Year 2021 Publication Nano Energy Abbreviated Journal Nano Energy
Volume 89 Issue B Pages 106473
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Piezoelectricity is considered to be one of the key functionalities in biomaterials to boost bone tissue regeneration, however, integrating biocompatibility, biodegradability and 3D structure with pronounced piezoresponse remains a material challenge. Herein, novel hybrid biocompatible 3D scaffolds based on biodegradable poly(3-hydroxybutyrate) (PHB) and reduced graphene oxide (rGO) flakes have been developed. Nanoscale insights revealed a more homogenous distribution and superior surface potential values of PHB fibers (33 +/- 29 mV) with increasing rGO content up to 1.0 wt% (314 +/- 31 mV). The maximum effective piezoresponse was detected at 0.7 wt% rGO content, demonstrating 2.5 and 1.7 times higher out-of-plane and in-plane values, respectively, than that for pure PHB fibers. The rGO addition led to enhanced zigzag chain formation between paired lamellae in PHB fibers. In contrast, a further increase in rGO content reduced the alpha-crystal size and prevented zigzag chain conformation. A corresponding model explaining structural and molecular changes caused by rGO addition in electrospun PHB fibers is proposed. In addition, finite element analysis revealed a negligible vertical piezoresponse compared to lateral piezoresponse in uniaxially oriented PHB fibers based on alpha-phase (P2(1)2(1)2(1) space group). Thus, the present study demonstrates promising results for the development of biodegradable hybrid 3D scaffolds with an enhanced piezoresponse for various tissue engineering applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000703592700002 Publication Date 2021-08-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2211-2855 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 12.343 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 12.343
Call Number UA @ admin @ c:irua:182579 Serial 7914
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Author Villarreal, R.; Lin, P.-C.; Faraji, F.; Hassani, N.; Bana, H.; Zarkua, Z.; Nair, M.N.; Tsai, H.-C.; Auge, M.; Junge, F.; Hofsaess, H.C.; De Gendt, S.; De Feyter, S.; Brems, S.; Ahlgren, E.H.; Neyts, E.C.; Covaci, L.; Peeters, F.M.; Neek-Amal, M.; Pereira, L.M.C.
Title Breakdown of universal scaling for nanometer-sized bubbles in graphene Type A1 Journal article
Year 2021 Publication Nano Letters Abbreviated Journal Nano Lett
Volume 21 Issue 19 Pages 8103-8110
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We report the formation of nanobubbles on graphene with a radius of the order of 1 nm, using ultralow energy implantation of noble gas ions (He, Ne, Ar) into graphene grown on a Pt(111) surface. We show that the universal scaling of the aspect ratio, which has previously been established for larger bubbles, breaks down when the bubble radius approaches 1 nm, resulting in much larger aspect ratios. Moreover, we observe that the bubble stability and aspect ratio depend on the substrate onto which the graphene is grown (bubbles are stable for Pt but not for Cu) and trapped element. We interpret these dependencies in terms of the atomic compressibility of the noble gas as well as of the adhesion energies between graphene, the substrate, and trapped atoms.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000709549100026 Publication Date 2021-09-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 12.712 Times cited 24 Open Access OpenAccess
Notes Approved Most recent IF: 12.712
Call Number UA @ admin @ c:irua:184137 Serial 6857
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Author Nematollahi, P.; Barbiellini, B.; Bansil, A.; Lamoen, D.; Qingying, J.; Mukerjee, S.; Neyts, E.C.
Title Identification of a Robust and Durable FeN4CxCatalyst for ORR in PEM Fuel Cells and the Role of the Fifth Ligand Type A1 Journal article
Year 2022 Publication ACS catalysis Abbreviated Journal Acs Catal
Volume Issue Pages 7541-7549
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Although recent studies have advanced the understanding of pyrolyzed

Fe−N−C materials as oxygen reduction reaction (ORR) catalysts, the atomic and

electronic structures of the active sites and their detailed reaction mechanisms still remain unknown. Here, based on first-principles density functional theory (DFT) computations, we discuss the electronic structures of three FeN4 catalytic centers with different local topologies of the surrounding C atoms with a focus on unraveling the mechanism of their ORR activity in acidic electrolytes. Our study brings back a forgotten, synthesized pyridinic Fe−N coordinate to the community’s attention, demonstrating that this catalyst can exhibit excellent activity for promoting direct four-electron ORR through the addition of a fifth ligand such as −NH2, −OH, and −SO4. We also identify sites with good stability properties through the combined use of our DFT calculations and Mössbauer spectroscopy data.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000823193100001 Publication Date 2022-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS full record; WoS citing articles
Impact Factor (up) 12.9 Times cited Open Access OpenAccess
Notes Basic Energy Sciences, DE-FG02-07ER46352 ; Fonds Wetenschappelijk Onderzoek, 1261721N ; Opetus- ja Kulttuuriministeri?; Department of Energy, DE-EE0008416 ; Approved Most recent IF: 12.9
Call Number EMAT @ emat @c:irua:189000 Serial 7073
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Author Cui, Z.; Meng, S.; Yi, Y.; Jafarzadeh, A.; Li, S.; Neyts, E.C.; Hao, Y.; Li, L.; Zhang, X.; Wang, X.; Bogaerts, A.
Title Plasma-catalytic methanol synthesis from CO₂ hydrogenation over a supported Cu cluster catalyst : insights into the reaction mechanism Type A1 Journal article
Year 2022 Publication Acs Catalysis Abbreviated Journal Acs Catal
Volume 12 Issue 2 Pages 1326-1337
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma-catalytic CO, hydrogenation for methanol production is gaining increasing interest, but our understanding of its reaction mechanism remains primitive. We present a combined experimental/computational study on plasma-catalytic CO, hydrogenation to CH3OH over a size-selected Cu/gamma-Al2O3 catalyst. Our experiments demonstrate a synergistic effect between the Cu/gamma-Al2O3 catalyst and the CO2/H-2 plasma, achieving a CO2 conversion of 10% at 4 wt % Cu loading and a CH3OH selectivity near 50% further rising to 65% with H2O addition (for a H2O/CO2 ratio of 1). Furthermore, the energy consumption for CH3OH production was more than 20 times lower than with plasma only. We carried out density functional theory calculations over a Cu-13/gamma-Al2O3 model, which reveal that the interfacial sites of the Cu-13 cluster and gamma-Al2O3 support show a bifunctional effect: they not only activate the CO2 molecules but also strongly adsorb key intermediates to promote their hydrogenation further. Reactive plasma species can regulate the catalyst surface reactions via the Eley-Rideal (E-R) mechanism, which accelerates the hydrogenation process and promotes the generation of the key intermediates. H2O can promote the CH3OH desorption by competitive adsorption over the Cu-13/gamma-Al2O3 surface. This study provides new insights into CO2 hydrogenation through plasma catalysis, and it provides inspiration for the conversion of some other small molecules (CH4, N-2, CO, etc.) by plasma catalysis using supported-metal clusters.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000742735600001 Publication Date 2022-01-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 12.9 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 12.9
Call Number UA @ admin @ c:irua:186416 Serial 7192
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Author Neyts, E.C.; van Duin, A.C.T.; Bogaerts, A.
Title Changing chirality during single-walled carbon nanotube growth : a reactive molecular dynamics/Monte Carlo study Type A1 Journal article
Year 2011 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 133 Issue 43 Pages 17225-17231
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The growth mechanism and chirality formation of a single-walled carbon nanotube (SWNT) on a surface-bound nickel nanocluster are investigated by hybrid reactive molecular dynamics/force-biased Monte Carlo simulations. The validity of the interatomic potential used, the so-called ReaxFF potential, for simulating catalytic SWNT growth is demonstrated. The SWNT growth process was found to be in agreement with previous studies and observed to proceed through a number of distinct steps, viz., the dissolution of carbon in the metallic particle, the surface segregation of carbon with the formation of aggregated carbon clusters on the surface, the formation of graphitic islands that grow into SWNT caps, and finally continued growth of the SWNT. Moreover, it is clearly illustrated in the present study that during the growth process, the carbon network is continuously restructured by a metal-mediated process, thereby healing many topological defects. It is also found that a cap can nucleate and disappear again, which was not observed in previous simulations. Encapsulation of the nanoparticle is observed to be prevented by the carbon network migrating as a whole over the cluster surface. Finally, for the first time, the chirality of the growing SWNT cap is observed to change from (11,0) over (9,3) to (7,7). It is demonstrated that this change in chirality is due to the metal-mediated restructuring process.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000297380900026 Publication Date 2011-10-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 13.858 Times cited 116 Open Access
Notes Approved Most recent IF: 13.858; 2011 IF: 9.907
Call Number UA @ lucian @ c:irua:92043 Serial 309
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Author Neyts, E.C.; van Duin, A.C.T.; Bogaerts, A.
Title Insights in the plasma-assisted growth of carbon nanotubes through atomic scale simulations : effect of electric field Type A1 Journal article
Year 2012 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 134 Issue 2 Pages 1256-1260
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Carbon nanotubes (CNTs) are nowadays routinely grown in a thermal CVD setup. State-of-the-art plasma-enhanced CVD (PECVD) growth, however, offers advantages over thermal CVD. A lower growth temperature and the growth of aligned freestanding single-walled CNTs (SWNTs) makes the technique very attractive. The atomic scale growth mechanisms of PECVD CNT growth, however, remain currently entirely unexplored. In this contribution, we employed molecular dynamics simulations to focus on the effect of applying an electric field on the SWNT growth process, as one of the effects coming into play in PECVD. Using sufficiently strong fields results in (a) alignment of the growing SWNTs, (b) a better ordering of the carbon network, and (c) a higher growth rate relative to thermal growth rate. We suggest that these effects are due to the small charge transfer occurring in the Ni/C system. These simulations constitute the first study of PECVD growth of SWNTs on the atomic level.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000301084300086 Publication Date 2011-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 13.858 Times cited 56 Open Access
Notes Approved Most recent IF: 13.858; 2012 IF: 10.677
Call Number UA @ lucian @ c:irua:97163 Serial 1673
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Author Neyts, E.C.; Shibuta, Y.; van Duin, A.C.T.; Bogaerts, A.
Title Catalyzed growth of carbon nanotube with definable chirality by hybrid molecular dynamics-force biased Monte Carlo simulations Type A1 Journal article
Year 2010 Publication ACS nano Abbreviated Journal Acs Nano
Volume 4 Issue 11 Pages 6665-6672
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Metal-catalyzed growth mechanisms of carbon nanotubes (CNTs) were studied by hybrid molecular dynamics−Monte Carlo simulations using a recently developed ReaxFF reactive force field. Using this novel approach, including relaxation effects, a CNT with definable chirality is obtained, and a step-by-step atomistic description of the nucleation process is presented. Both root and tip growth mechanisms are observed. The importance of the relaxation of the network is highlighted by the observed healing of defects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000284438000043 Publication Date 2010-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 13.942 Times cited 129 Open Access
Notes Approved Most recent IF: 13.942; 2010 IF: 9.865
Call Number UA @ lucian @ c:irua:84759 Serial 294
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Toward the Understanding of Selective Si Nano-Oxidation by Atomic Scale Simulations Type A1 Journal article
Year 2017 Publication Accounts of chemical research Abbreviated Journal Accounts Chem Res
Volume 50 Issue 50 Pages 796-804
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The continuous miniaturization of nanodevices, such as transistors, solar cells, and optical fibers, requires the controlled synthesis of (ultra)thin gate oxides (<10 nm), including Si gate-oxide (SiO2) with high quality at the atomic scale. Traditional thermal growth of SiO2 on planar Si surfaces, however, does not allow one to obtain such ultrathin oxide due to either the high oxygen diffusivity at high temperature or the very low sticking ability of incident oxygen at low temperature. Two recent techniques, both operative at low (room) temperature, have been put forward to overcome these obstacles: (i) hyperthermal oxidation of planar Si surfaces and (ii) thermal or plasma-assisted oxidation of nonplanar Si surfaces, including Si nanowires (SiNWs). These nanooxidation processes are, however, often difficult to study experimentally, due to the key intermediate processes taking place on the nanosecond time scale.

In this Account, these Si nano-oxidation techniques are discussed from a computational point of view and compared to both hyperthermal and thermal oxidation experiments, as well as to well-known models of thermal oxidation, including the Deal−Grove, Cabrera−Mott, and Kao models and several alternative mechanisms. In our studies, we use reactive molecular dynamics (MD) and hybrid MD/Monte Carlo simulation techniques, applying the Reax force field. The incident energy of oxygen species is chosen in the range of 1−5 eV in hyperthermal oxidation of planar Si surfaces in order to prevent energy-induced damage. It turns out that hyperthermal growth allows for two growth modes, where the ultrathin oxide thickness depends on either (1) only the kinetic energy of the incident oxygen species at a growth temperature below Ttrans = 600 K, or (2) both the incident energy and the growth temperature at a growth temperature above Ttrans. These modes are specific to such ultrathin oxides, and are not observed in traditional thermal oxidation, nor theoretically considered by already existing models. In the case of thermal or plasma-assisted oxidation of small Si nanowires, on the other hand, the thickness of the ultrathin oxide is a function of the growth temperature and the nanowire diameter. Below Ttrans, which varies with the nanowire diameter, partially oxidized SiNW are formed, whereas complete oxidation to a SiO2 nanowire occurs only above Ttrans. In both nano-oxidation processes at lower temperature (T < Ttrans), final sandwich c-Si|SiOx|a-SiO2 structures are obtained due to a competition between overcoming the energy barrier to penetrate into Si subsurface layers and the compressive stress (∼2−3 GPa) at the Si crystal/oxide interface. The overall atomic-simulation results strongly indicate that the thickness of the intermediate SiOx (x < 2) region is very limited (∼0.5 nm) and constant irrespective of oxidation parameters. Thus, control over the ultrathin SiO2 thickness with good quality is indeed possible by accurately tuning the oxidant energy, oxidation temperature and surface curvature.

In general, we discuss and put in perspective these two oxidation mechanisms for obtaining controllable ultrathin gate-oxide films, offering a new route toward the fabrication of nanodevices via selective nano-oxidation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000399859800016 Publication Date 2017-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-4842 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 20.268 Times cited 5 Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, 12M1315N ; Approved Most recent IF: 20.268
Call Number PLASMANT @ plasmant @ c:irua:142638 Serial 4561
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Author Ostrikov, K.; Neyts, E.C.; Meyyappan, M.
Title Plasma nanoscience : from nano-solids in plasmas to nano-plasmas in solids Type A1 Journal article
Year 2013 Publication Advances in physics Abbreviated Journal Adv Phys
Volume 62 Issue 2 Pages 113-224
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The unique plasma-specific features and physical phenomena in the organization of nanoscale soild-state systems in a broad range of elemental composition, structure, and dimensionality are critically reviewed. These effects lead to the possibility to localize and control energy and matter at nanoscales and to produce self-organized nano-solids with highly unusual and superior properties. A unifying conceptual framework based on the control of production, transport, and self-organization of precursor species is introduced and a variety of plasma-specific non-equilibrium and kinetics-driven phenomena across the many temporal and spatial scales is explained. When the plasma is localized to micrometer and nanometer dimensions, new emergent phenomena arise. The examples range from semiconducting quantum dots and nanowires, chirality control of single-walled carbon nanotubes, ultra-fine manipulation of graphenes, nano-diamond, and organic matter to nano-plasma effects and nano-plasmas of different states of matter.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000320913600001 Publication Date 2013-06-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-8732;1460-6976; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 21.818 Times cited 380 Open Access
Notes Approved Most recent IF: 21.818; 2013 IF: 18.062
Call Number UA @ lucian @ c:irua:108723 Serial 2639
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Author Neyts, E.C.; Ostrikov, K.K.; Sunkara, M.K.; Bogaerts, A.
Title Plasma Catalysis: Synergistic Effects at the Nanoscale Type A1 Journal article
Year 2015 Publication Chemical reviews Abbreviated Journal Chem Rev
Volume 115 Issue 115 Pages 13408-13446
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, render the process highly complex, and little is known about the factors leading to the often-observed synergy. This Review critically examines the catalytic mechanisms relevant to each specific application.
Address Department of Chemistry, Research Group PLASMANT, Universiteit Antwerpen , Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000367563000006 Publication Date 2015-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2665 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 47.928 Times cited 204 Open Access
Notes ECN and AB gratefully acknowledge financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant Number G.0217.14N. KO acknowledges partial support by the Australian Research Council and CSIRO’s OCE Science Leaders Program. MKS acknowledges partial support from US National Science Foundation through grants DMS 1125909 and EPSCoR 1355448 and also PhD students Babajide Ajayi, Apolo Nambo and Maria Carreon for their help. Approved Most recent IF: 47.928; 2015 IF: 46.568
Call Number c:irua:130001 Serial 3993
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